Wire feeding means



July 16, 1968 R. ULLMAN WIRE FEEDING MEANS 2 Sheets-Sheet l Filed Nov.

July 16, 1968 R. ULLMAN WIRE FEEDING MEANS 2 Sheets-Sheet 2 56 6 Filed Nov. 3, 1966 PR\OR ART United States Patent F 3,392,896 WIRE FEEDING MEANS Robert Ullman, Harrisburg, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed Nov. 3, 1966, Ser. No. 591,904 5 Claims. (Cl. 226-187) This invention relates to feeding devices for feeding two wires at a time along parallel paths.

Under some circumstances, it is desirable to feed two wires, rather than a single wire, by means of a single pair of wire feed wheels. For example, the US. patent to Schwalm et al., No. 3,019,679, shows a fully automatic lead making machine which feeds wire from a coil through a cutting and stripping zone in which the wire is cut, insulation is stripped from the cut ends, and contact terminals are crimped onto the cut ends. The productivity of machines of this type can be substantially doubled if a pair of wires are simultaneously fed into the cutting and stripping zone and both wires are simultaneously cut, stripped, and attached to the ends of terminals. Terminal applicators have been devised for simultaneously crimping two terminals onto the ends of two wires in modified machines of the Schwalm type, see US. Patent No. 3,239,924.

The feeding of a pair of wires with a single set of feed wheels is a relatively simple operation if the wires are of precisely the same diameter throughout their lengths. However, the wire contained in an individual coil or drum may vary considerably, for example, wire having a nominal diameter of 0.065 inch may have actual diameter in a single coil between the limits of 0.070 and 0.060 inch. Furthermore, two coils of wire having the same nominal diameter may have slightly dilferent diameters even if both wires are uniform throughout their lengths.

When a lead making machine of the type disclosed in the above-identified Schwalm et al. patent is modified to produce two leads during each cycle, it is usually desired to turn out two identical leads, having the same length, during each operating cycle. If the feed lengths of the two wires are different, the leads will not, of course, be identical.

Irregularities in the diameters of the wires as discussed above render the feeding of identical lengths of two wires by means of a single set of feed wheels impractical. If one of the wires being fed should increase in diameter slightly, the effect can be to force the feed rolls apart so that while the larger diameter wire will continue to be fed, the smaller diameter wire will slip relative to the feed Wheels so that the two leads fed durin a given time interval will be of unequal length.

It is an object of the invention to provide an improved means for feeding wire. A more specific object is to provide an apparatus for feeding two wires at a time by means of a single pair of feed wheels. A still further object is to provide a feeding apparatus for feeding two wires at a time which compensates for variations in the diameters of the wires. A still further object is to provide a pair of feed wheels for feeding two wires at a time which will be substantially equal lengths of the two wires during a given time interval.

These and other objects of the invention are achieved in a preferred embodiment of the invention comprising a pair of coplanar feed wheels mounted on parallel spaced-apart axes. The wheels normally have a common medial plane which is equidistant from the sides of the wheels and which extends transversely of the axes on which the wheels rotate. Wire guide means on the peripheries of the wheels are provided equally spaced from the common medial plane for guiding wires through the nip of the wheels on opposite sides of the medial plane. The wheels are arranged such that their peripheral por- 3,392,896 Patented July 16, 1968 tions can tilt during rotation of the wheels by a slight amount relative to the common medial plane under the influence of any pressure applied on one side or the other of the medial plane at the nip of the wheels. Thus, if two wires of precisely the same diameter are being fed, the wires will remain in contact with both Wheels and the same length of each wire will be fed during each revolution of the Wheels. If one of the wires should increase slightly in diameter during feeding (as by a manufacturing variation within the tolerance limits of the wire), the larger wire will cam the wheels apart on its side of the medial plane and tilt the peripheral portions of the wheels slightly. The wheels, will, as a result of this tilting, remain in contact with both of the wires and the same length of both wires will continue to be fed during each revolution of the feed wheels.

In the drawings:

FIGURE 1 is a schematic side view of a wire feeding system in accordance with the invention;

FIGURE 2 is a perspective view of a preferred form of feed wheel in accordance with the invention, two such wheels of the type shown in FIGURE 2 being required in the embodiment of FIGURE 1;

FIGURE 3 is a sectional view, with the parts assembled, of the wheel of FIGURE 2;

FIGURE 4 is a schematic sectional view through the nip of a pair of conventional feed wheels feeding two wires at a time, this view illustrating conventional prior art practice and the uneven feeding of the wires which results if one wire has a diameter slightly larger than the diameter of the other wire; and

FIGURE 5 is a schematic view through the nip section of a pair of feed wheels in accordance with the invention and illustrating the manner in which the peripheral portions of the wheels tilt to compensate for variations in the diameters of the wires being fed.

Referring first to FIGURE 1, a conventional method for feeding wire comprises a pair of feed wheel assemblies 6, 8 mounted on parallel spaced-apart drive shafts 20, 22 which in the ends of arms 10, 12. The arms 10, 12 are pivotally mounted at their opposite ends at 14, 16, and are spring biased by a spring 18 towards each other so that the peripheral portions of the rolls normally bear against each other. Wire is fed through the nip of the wheels by driving the feed wheels and the rolls are forced apart by the wire during feeding. The spring 18 thus functions to maintain the feed wheels in contact with the wires and to prevent slippage between the wheels and the wires.

Two wires 2, 4 can be fed through conventional rolls mounted as illustrated in FIGURE 1 by providing two peripheral grooves 58, 60- in each roll for the wires, see FIGURE 4. If the two wires are of precisely the same diameter, the rolls will be held against both wires by the spring 18 and equal lengths of both wires will befed during a given time interval. However, if one of the wires has a slightly larger diameter than the other wire, the larger wire, 4, will force the rolls 6a, 8a, apart and they will loose contact with the smaller diameter wire 2. During the interval when the enlarged diameter portion of the wire 4 is being fed through the rolls, the wire 2 'will not be fed so that during a given time interval, a greater length of the wire 4 will be fed than the wire 2. It should be pointed out that the differences in diarn eter of the wires 2, 4 is greatly exaggerated in FIG- URES 4 and 5 for purposes of illustration. In actuality, only a slight difference in diameter between the two wires will cause the effect illustrated in FIGURE 4 and result in uneven feeding rates.

The principle of the present invention is illustrated in FIGURE 5. The rolls in this case have peripheral portions 6b, 8b, which can be tilted slightly relative to the normal medial planes of the rolls. In FIGURE 5, it is assumed again that the wire 4 has a greater diameter than the wire 2 and tends to force the right hand sides of the peripheral portions of the rolls apart. Since the peripheral portions can tilt, the lefthand sides of the peripheral portions of the rolls move relatively towards each other and maintain their engagement with the wire 2. If the two wires 2, 4 are of the same diameter, the peripheral portions of the rolls would not be tilted with respect to the planes of the rolls as shown in FIGURE 5, but would be coplanar.

Tilting of the peripheral portions of the rolls can be achieved by a variety of ways and there is described below a specific and preferred embodiment of the invention for achieving this effect. It is also possible and within the scope of the invention to tilt the entire feed wheel assemblies as will be apparent after a reading of the specific embodiment described below.

Referring now to FIGURES 2 and 3, the preferred form of the invention comprises a feed wheel generally indicated at 24 having a tire 26 mounted on its periphery. Wheel 24 has a hub portion 28 by means of which it is coupled to the drive shaft means indicated at 20, 22 in FIGURE 1, and has sides 30, 32. The side 30 has a circular boss 34 thereon centered with respect to the axis of rotation and the wheel has a spherical surface 36 on its periphery, this surface appearing as an arcuate line in FIGURE 3. It should be mentioned that the curvature of this surface is somewhat exaggerated in FIGURE 3, in the interest of clarity of illustration and that the actual curvature will be somewhat less than that shown.

'Four recesses 38 extend inwardly on the sides 30, 32 at 90 intervals from the edges of the wheel, the recesses on the side 30 being in alignment with the recesses on the side 32 in the embodiment shown for best results as will be apparent as this description proceeds. Leaf springs 40 are mounted in these recesses and have tipportions 41 which extend over and into complementary recesses in the tires. These springs are secured to the wheels by suitable fasteners indicated at 43.

The tire 26 has an axial bore 42 and a counterbore 44 which defines an inwardly extending flange or lip 43 on its one side 47. A second counterbore is provided on the side 49 within which a retainer plate 52 is secured by means of fasteners 54. The tire is retained on the wheel by the lip or flange 43 on the side 47 and by the retainer plate 52 on the side 49. Recesses 50 are provided on the sides 47, 49 which extend radially outwardly from the surface of the counterbore 44 and which are dimensioned to receive the tip portions 41 of the spring members 40.

The leaf springs 40 fitting within the recesses 50 normally tend to maintain the tire centered on the periphery of the wheel with the medial plane of the wheel coinciding with the medial plane of the tire. However, these springs permit the tire to be tilted with respect to the wheel so that the medial plane of the tire will extend angularly with respect to the medial plane of the wheel. The springs also permit the tire to Wobble with respect to the wheel during rotation of the wheel. Finally, the springs 40 function as drive elements for the tire and prevent slippage of the tire with respect to the wheel The periphery 56 of the feed wheel assembly is provided with spaced'apart grooves 58, 60 which are equally distant from the medial plane of the wheel and tire and which are adapted to guide the two wires 2, 4 being fed.

When two feed wheels of the type shown in FIGURE 3 are used for a wire feeding assembly of the type shown in FIGURE 1, they will be exactly coplanar with each other so long as the two wires are of precisely the same diameter. However, if the diameter of one wire should increase slightly, the tires of the wheels will be tilted slightly as illustrated in FIGURE 5. In other words, the

sides of the tires on which the larger wire is being fed will be pushed apart and the nip of the wheels will be increased while the sides of the tires on which the smaller wire is being fed will move relatively towards each other. This may result in some compression of the wire on the left in FIGURE 5 but continuous contact with both wires will be maintained during the entire feeding operation. The wheels 24 remain coplanar during feeding of different size wires and the tires, therefore, are required to wobble with respect to the wheels. This wobbling motion of the tire is permitted by the retaining springs 40, as explained above, and the springs are alternately fiexed and relaxed during each revolution.

It will be apparent that the shifting of the tires permitting the tilting action is achieved by virtue of the spherical surface 36 on the wheels which bear against the surfaces 44 of the counterbores. Alternative methods might be used to achieve tilting of the peripheral portions of the feed wheels in order to achieve the same effect. For example, the wheels themselves might be mounted on tiltable axes. Also, other methods of mounting tiltable tires on the wheels might be employed.

The wire guide grooves 58, 60 on the tires are not necessarily required and the surfaces of the tires can be formed as cylindrical surfaces if desired. The grooves are, however, desirable in that the wires are prevented from moving laterally during feeding towards and away from the medial plane of the wheels. The invention can also be used to feed flat wires, such as fiat conductor cable or 300 ohm TV wire, and will compensate for variations in the thickness of the cable on its sides. The surfaces of the tires could be grooved or ungrooved for feeding such fiat material depending on the cross-section of the material.

The principles of the invention can be realized by using only a single feed wheel rather than two driven feed wheels as disclosed above. For example, a single feed wheel hav ing a tiltable tire of the type shown in the drawing might be mounted above a tiltable platform in the manner such that the wires being fed move between the periphery of the tire and the surface of the platform. If one of the wires were to increase in diameter during feeding, the platform and the single feed wheel would be automatically tilted, as illustrated in FIGURE 5, to compensate for the increase in diameter of the one wire and to insure that equal lengths of both wires will be fed. In order to reduce the friction of the wires on the platform, small rollers can be provided in the platform to support the wires.

In the foregoing description, it is assumed that the two wires being fed have the same nominal diameter, a situation which usually exists where a lead making machine of the type shown in the Schwalm et al. Patent No. 3,019,679, is modified to produce two finished electrical leads during each operating cycle. The invention can also be employed, however, where the wires have different nominal diameters. Under such circumstances, the tires on the wheels would always be tilted to accommodate the larger diameter wire and the degree to which they are tilted would vary to accommodate changes in the wire diameters as above described.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

What is claimed is:

1. Wire feeding means for feeding equal lengths of two wires simultaneously comprising, a pair of coplanar feed wheels mounted on parallel spaced-apart axes, said wheels having a common medial plane which is equidistant from the sides of said wheels and which extends normally of the axes of said wheels, tires tiltably mounted on the peripheries of said wheels, and tire holding means on the sides of said wheels extending over the sides of said tires normally maintaining said tires in 'an untilted condition relative to said medial plane but permitting said tires to tilt relative to said wheels in response to a change in the diameter of one of said wires. 2

2. A device as set forth in claim 1 wherein said tire holding means comprises leaf spring means disposed against said tires and said wheels.

3. A device as set forth in claim 2 wherein said leaf spring means drivingly connects said tires to said wheels.

4. A device as set forth in claim 1 wherein a spherical bearing surface is provided between said tires and said wheels to permit tilting of said tires.

5. Wire feeding means for feeding equal lengths of two wires simultaneously comprising, a pair of coplanar feed wheels mounted on parallel spaced-apart axes, said wheels having a common medial plane which is equidistant from the sides of said wheels and which extends normally of the axes of said wheels, 2. pair of wire guide means on each of said tires, said wire guide means being equidistant from said medial plane, spherical bearing surface means between said tires and said wheels to permit tilting of said tires relative to said wheels, and means normally holding said tires on said wheels in an untilted condition but permitting said tires to tilt relative to said wheels in response to a change in the diameter of said wires.

References Cited UNITED STATES PATENTS 357,342 2/1887 Seymour 226187 751,141 2/1904 Beker 226109 X 2,414,181 1/1947 Vandersee 226-109 X M. HENSON WOOD, IR., Primary Examiner.

J. P. MULLINS, Assistant Examiner. 

1. WIRE FEEDING MEANS FOR FEEDING EQUAL LENGTHS OF TWO WIRES SIMULTANEOUSLY COMPRISING, A PAIR OF COPLANAR FEED WHEELS MOUNTED ON PARALLEL SPACED-APART AXES, SAID WHEELS HAVING A COMMON MEDIAL PLANE WHICH IS EQUIDISTANT FROM THE SIDES OF SAID WHEELS AND WHICH EXTENDS NORMALLY OF THE AXES OF SAID WHEELS, TIRES TILTABLY MOUNTED ON THE PERIPHERIES OF SAID WHEELS, AND TIRE HOLDING MEANS ON THE SIDES OF SAID WHEELS EXTENDING OVER THE SIDES OF SAID TIRES NORMALLY MAINTAINING SAID TIRES IN AN UNTILTED CONDITION RELATIVE TO SAID MEDIAL PLANE BUT PERMITTING SAID TIRES TO TILT RELATIVE TO SAID WHEELS IN RESPONSE TO A CHANGE IN THE DIAMETER OF ONE OF SAID WIRES. 